Corrugator double-backer blanket



Dec. 23, 1958 R. VOLLRATH coRRuGAToR DOUBLE-BACKER BLANKET 2Sheets-Sheet l l HEM RES/suur Filed Nov. 15, 1955 SYNTHETIC SURF/1 CEYR/VS HEAT RAS/STAA/T .SYNTHETIC JUFA CE VAR/V5 M//L Tl- WEFT PLA ,VE

WOVEN FABRIC PORT/0N 0F Caro/V MRA/5 1N VENTOR R/CHARD VOLL RAT/'l BY.9m L M ATTORNEY Dec. 23, 1958 R. voLLRATH coRRUGAToR DOUBLE-BACKERBLANKET 2 Sheets-Sheet 2 Filed Nov. 15, 1955 INVENTOR RICHARD VOLL/2A THATTORNEY United States Patent O CORRUGATOR DOUBLE-BACKER BLANKET RichardVollrath, Easton, Pa., assigner to Victor Balata & Textile BeltingCompany, Easton, Pa.

Application November 15, 1955, Serial No. 546,951

5 Claims. (Cl. 139-408) The present invention relates to the manufactureof corrugated paper board and more specifically to an improvedinterwoven blanket for use in the manufacture of such board.

According to one prior art practice, corrugated paper board is formed byadhesively securing a corrugated paper web between two paper liners.Each liner comes from a separate roll and each has adhesive coatingapplied to the inner side thereof. The adhesive material is usuallyapplied as an aqueous solution containing sodium silicate and otheringredients. A third sheet from a third roll is corrugated and broughttogether with the liners to form a wet laminated board which isforthwith passed through a drying device, called a double-hacker. Thisdevice comprises a heating bed made up of a series of upwardlyfaced,steam-heated hot plates and an endless corrugator blanket above the bedwith its lower run adapted to overlie the heated plates. This blanketserves the several purposes of transporting the corrugated board overthe heated plates, absorbing moisture from the Wet board and weightingthe board to hold it in firm contact with the heated plates while theadhesive is being set and dried.

In practice, the blanket is made in two sections with a pair of belts ofequal width running side by side to cover the full width of the heatingplates. To hold the belts in proper running position, vertical guiderolls are arranged on the outside edges of the two blankets and a metalplate divider is arranged between the two belts to prevent doubling upor over-riding of the belts.

In manufacturing corrugated paper board in accordance with this priorart, one difficulty is that the blankets on any one machine arenecessarily of standard width, whereas the board being formed is ofvarying width. Thus, in fabricating the narrower widths of corrugatedpaper board the outer portions of the blanket come into direct contactwith the face of the hot plates and its outer or marginal portions arethus subjected to unreasonably high temperature and to abrasionresulting from deposits of the adhesive on the face of these hot plates.Over a period of time, ordinary all-cotton blankets become badly worn attheir marginal portions; they also tend to be charred in the same area.As a result of this, the water-absorbing qualities of the blanket areseriously reduced and there is a change in the thickness of thesemarginal portions. The decreased water absorbing qualities causesblistered and defective board, and the uneven thickness interferes withthe even iron-down effect which is required for producing smooth,constant thickness, high quality corrugated paperboard. Anotherdifficulty is that the guide rolls and the divider continually abradethe edges of the blanket, causing ravelling of the edge yarns.

One object of the present invention is to provide a method of producinguniform corrugated paper board which is free of blisters and one whichis smoothly ironed down. Another object of this invention is to providea corrugator' blanket which has a greatly increased wear life. Stillanother object of this invention is the substantial eliminationofcharring of the marginal portions Patented Dee. 23, 1958 of corrugatorblankets during the production of corrugated board of a width less thanthe width of the blanket being used. Another object of the invention isthe elimination of ravelling of the edges of corrugator blankets. An-vother object of the invention is the realization of the aforementionedobjects without substantially reducing the water absorptioncharacteristics of any portion of the corrugator blanket. Other objectsof the invention will be more readily apparent from the followingdescription and the accompanying drawings.

The objects of this invention are accomplished by the use of aninterwoven corrugator blanket in which marginal portions of theplate-engaging faces are surfaced with heat resistant, abrasionresistant, synthetic yarns, and the remainder of the interwoven blanketis constructed of cotton yarns for the purpose of retaining the waterabsorptive characteristics required for corrugator blankets.` Inasmuehas` the surface of interwoven eorrugating blankets is normally composedof only warpyarns, all of the synthetic material used in corrugatorblankets in accordance with this invention is incorporated in the warpyarns. Inasmuch as it has been found desirable to maintain the waterabsorbency characteristics of the belt, the synthetic yarns are includedonly in such warps as come to the surface of the interwoven structure.Ordinarily, corrugator blankets are interwoven with about ten to twelveWarp yarns in any given vertical plane, and with binder warps extendingfrom bottom to top throughout the interwoven structure. In suchconstructions, only three of the top warps in any vertical plane come tothe surface. In accordance with this invention, only these three surfacewarp yarns are composed of synthetic, heat resistant material, whereasthe other nine warp yarns as well as the binder yarns and the fillingyarns are made of cotton. Accordingly, it will be seen that even in themarginal portions Where the heat resistant yarns are incorporated, aboutto 80% of the yarns are made of cotton for the purpose of retaining thewater absorptive capacity of the blanket as a whole.

The width of the heat resistant marginal facing is determined by thevariation of widths of corrugated material being fabricated in any givenplant. Some manufacturers will prefer to have the entire face of theblanket composed of heat resistant yarns, whereas others prefer to haveonly marginal portions so constructed. It has been found that apractical minimum Width for these marginal reinforcements is about 25%of the total width of the blanket.

ln another form of the invention, ravelling of the blanket edges isprevented by also using Daeron in all the warp yarns for a distanceextending inwardly for about an inch or less. Thus, a blanketconstructed in accordance with the present invention will include multiplanes of cotton filling yarns, cotton binder warps and multi planes ofinterwoven warps, all composed of cotton with the sole exception ofsurface warp yarns extending inwardly from the margin of the blanket forat least 25% of its width, and possibly with the additional exception ofthe extreme edge on selvedge warp yarns to prevent ravelling fromabrasion by the guide rolls and the divider.

Any of the several known heat resistant synthetic yarns may be used inthe marginal surface warps of the corrugator blanket made according tothe present invention. Such materials include yarns made wholly orpartly from lament Daeron, filament nylon, filament Orlon, spun fibrousDaeron, spun brous nylon, spun brous Orlon, spun mixtures of thesematerials and other such materials. One difficulty to be avoided is theuse of yarns which have different shrinkage and stretch properties fromthose of ordinary cotton yarns. lt has been found that the preferredmaterial is spun Daeron (a polyester ber).

Although this specification is directed primarily to interwovencorrugator belts, it is possible to use the teaching of this inventionin the manufacture of multiply belts wherein separate plies are heldtogether by binder yarns. In such constructions only thewarps of thesurface ply would be made of'Dacron and the remaining warpswould becomposed whollyof ,cotton fibers. Likewise, it is` `possible to provideheat resistant ymarginal,.faces `at both ,sides of the blanket to makeit reversible. Thoseskilled inthe artwill realize that othermodifications-of .the invention may be made without departing from thescope of the appendedclaims. The gist of this invention is theincorporation vinto acorrugator .blanket of a minimum number of heatresistant, abrasionresistant syntheticwarp yarns to provide resistanceto charring `and abrasion while retaining a maximum numberlrof .cottonyarns to retain the absorbency characteristicsrequired for a corrugatorblanket. Thus, the relationship between-the amount of cotton yarn andthe amount of Dacron or other similar yarn is a critical factor inthepresent invention.

lt will also be realized by those skilled in the art that the provisionof all Daeron yarns at the extreme edge ofselvage of the corrugatorblanket is a separate, though related,improvement with respect to theheat resistant surface at the marginal portions of the corrugatorblanket.

vThe inventionv will be better `understood by reference totheaccompanying drawings in which:

Fig. 1 is a schematic representation of a portion of a corrugatorblanket having one marginal surfacemade .0f heat resistant, abrasionresistant yarns.

Fig. 2 is a schematic representation of another form of the inventionshowing a po-rtion of a corrugator blanket provided with both an edgeportion and a marginal surface composed of heat resistant, abrasionresistant materials.

. Fig. 3 is a schematic representation of the entire blanket partiallyshown in Fig. 1.

Fig. 4 is aschematic representation of the entire blanket partiallyshown in Fig. 2.

Fig Sis a schematic Vrepresentation 4of a blanket having both 'margins4constructed in accordance with the .disclosure-of Figs. 1 and 3.

`Fig. 6 is a-schematic representation of a blanket having-both marginsand edges constructed in accordance withthe disclosure of Figs. 2 and 4.

Fig. 7is a schematic representation of a blanket having one entiresurface composed of heat resistant yarns.

. Fig.l 8 is a schematic representation of a blanket having one entire'surface and both edges made of heat resistant yarns.

Fig. 9*.is a schematic cross sectional view illustrating Vthe exactweaving construction of the marginal portion of a corrugator blanketmade in accordance With the present invention.

Fig. 10 is a schematic representation of a corrugating process andapparatus embodying the improvement of the present invention.

Referring now to the schematic representation of a corrugatingoperationv illustrated in Fig. 10, it will be seen that three rolls ofpaper 10, 12 and 14 feed individual paper webs to a corrugatingassembly. Liner web .16 .has its underside coated with an aqueousadhesive by means illustrated diagrammatically at 18 while liner 20 hasits upperside coated with adhesive by means illustrated at 22 and web 24is corrugated by means illustrated diagrammatically at 26. These threewebs are brought together to form a wet laminated board 27 by meansillustrated diagrammatically at 28. Board 27 is then passed through anapparatus known in the trade asa double backer and indicated generallyat 30. The double hacker includes a bed of steam heated plates 32 and anendless ,corrugator blanket 34. The corrugator-'blanket is made up oftwo belts of equal Width running side by side and is held in properoperative relationship by a divider between the two belts an-d a seriesof guide rolls at the edges of the belts, not shown. The double backersmooths the laminated board and at the same time `dries and sets theadhesive. The heat for this operation is supplied by the plates on bed32 and much of the moisture is taken-off by being absorbed into blanket34. Finished board 27 is cut into sheets and stacked for use.

The preferred Weaving construction for -corrugator blankets 34, isillustrated diagrammatically in Fig. 9. A plurality of weft or llingends indicated at 38 are interwoven with a plurality of warp yarns 39,40, 41, `42,l 43, 44, 45, 46, 47, 48, 49 and .50, whereby there are noplies as such, but there are in eifect six weft planes. It will be notedthat only warps 39, 40 and 41 come to the upper surface of the blanket,the remaining warps being either buried inside the body ,of the blanketor exposed on the lower side. .In this preferred construction .the totalthickness of the belt is about 3A; of an inch and the weaving is quitetight to make a firm, hard, boardy structure. Such. a. belt is desirablein weightingdown the corrugated board both for firmness of the adhesiveboard and for proper contact with heated plates. The hardness .of theblanket also serves to iron down .or smooth thecorrugated bo-ard.Although the illustration shows only one warp end in any Vverticalportion of the weaving pattern, the actual weave includes threewarp endsrunning as one, a practice which is sometimes referred to as weavingthree ends up. In the construction according to thisinvention all oftherfiling yarns 38vandall of the warp yarns 42 to 5t), inelusive,.arecomposed of cotton as are all of the warp binder yarns, not illustrated.v Ward ends 39, 40 and 41 are .composed of .spun Daeron yarns or othersimilar heat; resistant, abrasion resistant materials if desired.

Referring now to Figs. 1 and 3 it will be seen that-in this form of theinvention warps 39, 40 and 41 are composed of Daeron at one marginy ofthe blanket fora distance extending inwardly several inches to .form` aheat resistant marginal surface 60. The remaining .portion-of theblanket forms a body 62 composed of cotton for the purpose of retainingthe moisture absorbency characteristics of the blanket and this has theadded advantage of keeping the cost of this improvement .at a minimumlevel.

Similarly in Figs.' 2 and 4 there `is a corrugator blanket having acotton body 70 provided with a heat resistant, abrasio-n resistantmarginal portion 72 and an edge portion 74 in which all of the ordinaryedge warps are made of Daeron for a distance extending inwardly forabout1/2 inch.

Another closely-related structure is shown in Fig. 5 where a blanketisprovided with a cotton body and two heat resistant, abrasion resistantmarginal portions 81 and S2. Yetanotherform of the invention,illustrated in Fig. 6, showsa corrugator blanket having a cotton body90, two heat resistant, abrasion resistant marginal portions 91 and 92,and two heat resistant, abrasion resistant edge portions 93 and 94.

Another satisfactory form of the invention is shown in Fig.v 7 where acorrugator blanket includes acotton body and a heat resistant, abrasionresistant surface 102 extending all the way acrossjits entire width. Inthe modification of Fig. 8, a blanket is provided with a cotton body110, a heat resistant, abrasion resistant surface 112 extending acrossthe full `width of the blanket and two heat resistant, abrasionresistantl edges 113 and 114. Other modifications along thesesame'lines-will be obvious to those skilled in the art.

I claim:

1. -A corrugator blanket --comprising an interwoven multi-weft-planeAfabric having a thicknessof more Athan one-quarter of an inch and lessthan one inch, said fabric being woven from cotton yarns with ltheexceptionkof the surface yarns thereof adjacent its edges, the surfaceyarns at one side of the fabric adjacent at least one of said edgesbeing warp yarns and consisting of heat resistant, abrasion resistant,synthetic, organic, polymeric yarns, said fabric having a plurality ofcotton yarns underlying said synthetic yarns to provide absorbency.

2. A corrugator blanket comprising binder warp yarns, warp yarns andfilling yarns interwoven into a fabric of multiweft planes having auniform thickness of between about 1/4 inch and 1 inch, all of saidyarns cornprising cotton with the exception of the surface warp yarnsadjacent the edges of the'fabric, and the surface yarns on at least oneside of the fabric adjacent at least one of said edges of the saidfabric being `warp yarns and consisting of heat resistant, abrasionresistant, synthetic, organic, polymeric yarns.

3. A corrugator blanket comprising cotton and heat resistant, abrasionresistant, synthetic, organic, polymeric yarns interwoven into a hardfabric having multi-weft planes with said cotton yarns forming oneentire side surface of said blanket, a major portion including at leastthe lateral center of the other side of the blanket and the yarns notappearing at any surface ofthe blanket, and said polymeric yarns forminga portion of said other 6 surface extending laterally inwardly from atleast one side of said blanket, all of said polymeric yarns being warpyarns and there being no filling yarns at the side surfaces of saidblanket.

4. A blanket as set forth in claim 3 wherein the width of the surfaceformed by said polymeric yarns is from about 8 to 12 inches.

5. A blanket as set forth in claim 3 wherein said polymerio yarns form aportion of said other surface extending laterally inwardly from eachedge of said blanket.

References Cited in the le of this patent UNITED STATES PATENTS1,504,218 Crowell Aug. 12, 1924 1,750,493 Spencer Mar. 11, 19301,812,148 Hinde June '30, 1931 2,208,090 Whittier July 16, 19402,210,290 Heinsohn Aug. 6, 1940 2,219,065 Bruker et al. Oct. 22, 19402,400,327 Womble May 14, 1946 2,664,922 Walters et al. Ian. 5, 1954FOREIGN PATENTS 500,262 Great Britain Feb. 6, 1939

1. A CORRUGATOR BLANKET COMPRISING AN INTERWOVEN MULTI-WEFT-PLANE FABRICHAVING A THICKNESS OF MORE THAN ONE-QUARTER OF AN INCH AND LESS THAN ONEINCH, SAID FABRIC BEING WOVEN FROM COTTON YARNS WITH THE EXCEPTION OFTHE SURFACE YARNS THEREOF ADJACENT ITS EDGES, THE SURFACE YARNS AT ONESIDE OF THE FABRIC ADJACENT AT LEAST ONE OF SAID EDGES BEING WARP YARNSAND CONSISTING OF HEAT RESISTANT, ABRASION RESISTANT, SYNTHETIC,ORGANIC, POLYMERIC YARNS, SAID FABRIC HAVING A PLURALITY OF COTTON YARNSUNDERLYING SAID SYNTHETIC YARNS TO PROVIDE ABSORBENCY.